Activity for the week of 9 December-15 December 2015

The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.

INSIVUMEH reported that during 10-12 December explosions at Fuego generated ash plumes that rose 450-950 m above the crater and drifted as far as 12 km W and SW. Shock waves from the explosions vibrated nearby homes. Incandescent material was ejected 200 m high, landed on the flanks, and then formed small avalanches in the Santa Teresa (SW), Taniluyá (SW), and Las Lajas (SE) drainages. Block avalanches reached vegetated areas during 11-12 December. Activity increased during the night of 14-15 December, characterized by an increased number of explosions (4-6 per hour). Ash plumes rose almost 1 km high and drifted 10-15 km NE, E, and SE. Two 800-m-long lava flows were active in the Trinidad (S) and Santa Teresa drainages.

PHIVOLCS reported that two volcanic earthquakes at Kanlaon were accompanied by a one-minute, low-energy, gray ash emission at 0513 on 11 December. Observers noted ash emissions at 0951, 1008, 1140, and 0101 on 13 December which rose 200-300 m and drifted SW. The emissions were not detected by the seismic network, indicating a shallow source. Trace amounts of ashfall were reported in Sitio Bais, Brgy Yubo, and La Carlota City on the W flank and Brgy Sag-ang and La Castellana on the SW flank. The Alert Level remained at 1 (on a scale of 0-5).

Based on INETER and SINAPRED reports, activity at Momotombo continued through 10 December. Fieldwork revealed a small, incandescent, circular crater halfway up Momotombo's E flank that was fuming during the morning on 6 December. An explosion on 7 December destroyed part of the crater. On 10 December SINAPRED reported that material had been accumulating in the crater since the beginning of the eruption on 1 December. Seismicity during 9-14 December was low and stable.

Based on satellite and webcam images, the Darwin VAAC reported that during 9-15 December ash plumes from Tengger Caldera's Bromo cone rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 45-65 km NE, NW, W, and SW. On 15 December BNPB reported that activity at the volcano remained high; gray-brown ash plumes rose 1.5 km above the crater and drifted W and NW. Weak rumbling was noted.

KVERT reported quiet conditions at Zhupanovsky after a partial collapse of the S central sector on 27 and 30 November. Satellite images detected a very weak thermal anomaly over the volcano on 4 and 7 December. Moderate levels of fumarolic activity continued. On 10 December the Aviation Color Code was lowered to Yellow.

Ongoing Activity

Based on satellite images, wind data, webcam images, and notices from the Mexico City MWO, the Washington VAAC reported that during 9 and 13-15 December ash plumes from Colima rose to altitudes of 4.6-7.6 km (15,000-25,000 ft) a.s.l. and E, ENE, and NE.

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 9-15 December ash plumes from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted as far as 200 km W, NE, E, and SE.

Based on observations conducted at the Karangetang Volcano Observation Post in the village of Salili, PVMBG reported during 3-10 December that the lava dome was incandescent at night. Variable amounts of white emissions rose as high as 200 m above Main Crater. RSAM values had been stable since 6 November. The Alert Level remained at 3 (on a scale of 1-4); visitors and residents were warned not to approach Karangetang within a 4-km radius.

HVO reported that seismicity beneath Kilauea's summit, upper East Rift Zone, and Southwest Rift Zone was at background levels during 9-15 December. The lava lake continued to circulate and spatter in the Overlook vent. Webcams recorded multiple incandescent outgassing vents within Pu'u 'O'o. A new incandescent and fuming vent, reported on 10 December, appeared to be from a small collapse into an older, but still hot lava tube. The June 27th NE-trending lava flow continued to be active within 6 km NE of Pu'u 'O'o Crater, burning some areas of forest.

Although inclement weather sometimes obscured views of Lokon-Empung's Tompaluan Crater, PVMBG reported that during 3-10 December observers at the post in Kakaskasen Tomohon (North Sulawesi, 4 km from the crater), saw white plumes rising as high as 400 m above the crater. Seismicity fluctuated, but the seismic spectral amplitude measurement (SSAM) had shown a gradually increasing trend over the previous 3-4 months. The Alert Level remained at 3 (on a scale of 1-4). Residents and tourists were reminded not to approach the crater within a radius of 2.5 km.

Instituto Geofísico del Perú (IGP) Observatorio Volcanológico del Sur (OVS) reported that during 9-14 December the number of volcano-tectonic (VT) earthquakes less than 6 km from the crater sharply increased; VT earthquakes in general were focused within 8 km of the crater at depths ranging from 3 to 15 km. White fumarolic plumes were steadily emitted, while bluish gasses were more sporadically observed. Gas plumes rose 800-1,400 m above the crater’s base. The Buenos Aires VAAC reported that during 11-12 December Sabancaya's webcam recorded weak emissions with minor amounts of ash.

Based on information from PVMBG, the Darwin VAAC reported that on 13 December an ash plume from Sinabung rose to an altitude of 4.3 km (15,000 ft) a.s.l. and drifted SW. On 15 December an ash plume rose to an altitude of 4 km (14,000 ft) a.s.l. and drifted 75 km W.

On 10 December the GeoNet Data Centre reported that minor unrest continued at White Island based on results from recent routine monitoring. During the previous week scientists visited the island and detected continuing (over the previous three months) ground deformation and a small increase in CO2 soil gas flux. Small temperature increases were also measured at the hottest fumarole and from the lake water. Volcanic tremor levels fluctuated, but overall showed a consistent rise over the last two months; they remained below those observed in 2012 when unrest was stronger and small eruptions occurred. Airborne gas measurements revealed an increase in CO2 and a decrease in SO2 gas fluxes. The Volcanic Alert Level remained at 1 and the Aviation Colour Code remained Green.

On 15 December, the Vanuatu Geohazards Observatory stated that the Alert Level for Yasur remained at 2 (on a scale of 0-4) and that explosions had become more intense. VGO reminded residents and tourists that hazardous areas were near and around the volcanic crater, and that volcanic ash and gas could reach areas impacted by trade winds.

Use the dropdowns to choose the year and week for archived Weekly Reports.

Year

Week

News Feeds and Google Placemarks

The RSS (Really Simple Syndication) feed is identical to the Weekly Volcanic Activity Report minus some features including the header information (latitude and longitude and summit elevation), the Geologic Summary, and a link to the volcano's page from the Global Volcanism Program. Each volcano report includes a link from the volcano's name back to the more complete information in the Weekly Volcanic Activity Report on the Smithsonian website.

The CAP (Common Alerting Protocol) feeds are XML files specifically formatted for disaster management. They are similar in content to the RSS feed, but contain no active links.

A Google Earth network link for the Weekly Volcanic Activity Report can be loaded into the free Google Earth software, and in turn will load placemarks for volcanoes in the current weekly report. Placemark balloons include the volcano name, report date, report text, sources, and links back to the GVP volcano page for that volcano and to the complete Weekly Report for that week.

Criteria & Disclaimers

Criteria

The Weekly Volcanic Activity Report does not necessarily include all volcanic activity that occurred on Earth during the week. More than a dozen volcanoes globally have displayed more-or-less continuous eruptive activity for decades or longer, and such routine activity is typically not reported here. Moreover, Earth's sea-floor volcanism is seldom reported even though in theory it represents the single most prolific source of erupted material. The Weekly Volcanic Activity Report summarizes volcanic activity that meets one or more of the following criteria:

- A volcano observatory raises or lowers the alert level at the volcano.
- A volcanic ash advisory has been released by a volcanic ash advisory center (VAAC) stating that an ash cloud has been produced from the volcano.
- A verifiable news report of new activity or a change in activity at the volcano has been issued.
- Observers have reported a significant change in volcanic activity. Such activity can include, but is not restricted to, pyroclastic flows, lahars, lava flows, dome collapse, or increased unrest.

Volcanoes are included in the "New Activity/Unrest" section of the Weekly Volcanic Activity Report if the activity occurs after at least 3 months of quiescence. Once a volcano is included in the "New Activity/Unrest" section, updates will remain in that section unless the activity continues for more than 1 month without escalating, after which time updates will be listed in the "Continuing Activity" section. Volcanoes are also included in the "New Activity/Unrest" section if the volcano is undergoing a period of relatively high unrest, or increasing unrest. This is commonly equal to Alert Level Orange on a scale of Green, Yellow, Orange, Red, where Red is the highest alert. Or alert level 3 on a scale of 1-4 or 1-5.

It is important to note that volcanic activity meeting one or more of these criteria may occur during the week, but may not be included in the Weekly Volcanic Activity Report because we did not receive a report.

Disclaimers

1. The Weekly Volcanic Activity Report is intended to provide timely information about global volcanism on a weekly basis. Consequently, the report is generated rapidly by summarizing volcanic reports from various sources, with little time for fact checking. The accuracy of the Weekly Volcanic Activity Report is dependent upon the quality of the volcanic activity reports we receive. Reports published in the Bulletin of the Global Volcanism Network are monthly, and more carefully reviewed, although all of the volcanoes discussed in the Weekly Volcanic Activity Report are not necessarily reported in the Bulletin. Because of our emphasis on rapid reporting on the web we have avoided diacritical marks. Reports are updated on the Weekly Volcanic Activity Report web page as they are received, therefore information may be included regarding events that occurred before the current report period.

2. Rapidly developing events lead to coverage that is often fragmentary. Volcanoes, their eruptions, and their plumes and associated atmospheric effects are complex phenomena that may require months to years of data analysis in order to create a comprehensive summary and interpretation of events.

3. Preliminary accounts sometimes contain exaggerations and "false alarms," and accordingly, this report may include some events ultimately found to be erroneous or misleading.

4. Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.

5. USGS Disclaimer Statement for this Website:

Information presented on this website is considered public information and may be distributed or copied. Use of appropriate byline/photo/image credit is requested. We strongly recommend that USGS data be acquired directly from a USGS server and not through other sources that may change the data in some way. While USGS makes every effort to provide accurate and complete information, various data such as names, telephone numbers, etc. may change prior to updating. USGS welcomes suggestions on how to improve our home page and correct errors. USGS provides no warranty, expressed or implied, as to the accuracy, reliability or completeness of furnished data.

Some of the documents on this server may contain live references (or pointers) to information created and maintained by other organizations. Please note that USGS does not control and cannot guarantee the relevance, timeliness, or accuracy of these outside materials.

For site security purposes and to ensure that this service remains available to all users, this government computer system employs software programs to monitor network traffic to identify unauthorized attempts to upload or change information, or otherwise cause damage. Unauthorized attempts to upload information or change information on this website are strictly prohibited and may be punishable under the Computer Fraud and Abuse Act of 1986 and the National Information Infrastructure Protection Act. Information may also be used for authorized law enforcement investigations. (Last modified September 21, 1999.)

An RSS (Really Simple Syndication) feed for the Weekly Volcanic Activity Report first made available on 5 March 2008 can be utilized with the aid of various free downloadable readers. The report content of the news feed is identical to the Weekly Volcanic Activity Report minus some features including the header information (latitude and longitude and summit elevation), the Geologic Summary, and a link to the volcano's page from the Global Volcanism Program. Each volcano report includes a link from the volcano's name back to the more complete information in the Weekly Volcanic Activity Report on the Smithsonian website. On 12 March 2009, GeoRSS tags were added so that the latitude and longitude for each volcano could be included with the feed.

At the end of each individual report is a list of the sources used. We would like to emphasize that the World Organization of Volcano Observatories (WOVO) website (http://www.wovo.org/) lists the regional volcano observatories that have the most authoritative data for many of these events.

A Google Earth network link for the Weekly Volcanic Activity Report was first made available on 1 April 2009. This file can be loaded into the free Google Earth software, and in turn will load placemarks for volcanoes in the current weekly report. Placemark balloons include the volcano name, report date, report text, sources, and links back to the GVP volcano page for that volcano and to the complete Weekly Report for that week.